It is planned to apply the stochastic model developed earlier to breast cancer issues associated with the U.S. population. Among the issues which will be studied are: estimating the U.S. breast cancer mortality for the period 2005-2020;investigate mortality for sub-populations;e.g. African-American, uninsured population and various scenarios;continue investigations of optimal screening schedules;investigate the role of the underreporting in SEER of invasive breast cancer following DCIS;investigate the influence on mortality if the number of women taking tamoxifen or reloxifene as a preventive agent is increased;develop a public web site (a) which will allow investigators to make use of our theoretical breast cancer model and (b) to communicate to the general public the breast cancer predicted mortality and false positive rate for any screening program.